The present invention relates to a dynamic orthosis for people suffering from severe dysmetria and the like, and more particularly to such an orthosis which dampens rapid dysmetric relative movement more than slow controlled relative movement.
Patients suffering from neurological conditions affecting the cerebellum or its connections, such as multiple sclerosis, resulting in severe dysmetria may have such severe intention tremors (especially those involving all motions and joints moving the upper extremities) that the daily tasks of life, such as even the simplest self-feeding, becomes practically impossible. Such non-functional tremors may occur across any major joint connecting proximal and distal body portions, for example, the neck connecting the head and body (i.e., titubation), the elbow connecting the upper arm and forearm (i.e., dysmetria), the knee connecting the thigh and lower leg (i.e., dysmetria), etc. For the purposes of the present invention, all of these will be referred to as dysmetria.
The conventional orthotic devices for use with such patients are primarily constraints on the possible movement of the patient rather than dampeners which permit desired controlled movement while filtering out undesired dysmetria movements. U.S. Pat. No. 4,237,873 discloses a cerebral palsy arm and hand brace which utilizes a spring-loaded piston-piston rod extension-contraction unit to control tremors in a patient's arm. One end of the brace must be fastened to a relatively fixed rigid structure such as the back of a chair, the wheelchair frame, or a back plate strapped to the patient. Additionally, the brace involves several rotatable joints which add to the complexity and cost of the device, introduce additional maintenance problems, and the like.
Accordingly, it is an object of the present invention to provide a dynamic orthosis which incorporates a proportional resistance across a major joint connecting proximal and distal body portions.
Another object is to provide such an orthosis which dampens rapid non-functional dysmetric relative movements of the proximal and distal body portions more than slow controlled relative movements thereof.
It is also an object to provide such an orthosis which comprises a connected pair of orthotic coupling means and a resistance means, with the resistance means being connected to the pair of connected orthotic coupling means only by a pair of pivot joints.
It is another object to provide such an orthosis which is comfortable and convenient to wear.
It is a further object to provide such an orthosis which is simple and economical to manufacture, use and maintain.